CDs and DVDsCDs and DVDs

Are types of optical Are types of optical storage media that storage media that consists of a flat, consists of a flat, round, portable disc round, portable disc made of metal plastic made of metal plastic and lacquer.and lacquer.

Store software, data, Store software, data, digital photographs, digital photographs, movies, and musicmovies, and music

Characteristics of CDs and DVDsCharacteristics of CDs and DVDs

Are not magnetic media, instead they are Are not magnetic media, instead they are optical media that store items such as data optical media that store items such as data and instructionsand instructions

Uses microscopic pits (indentations) and Uses microscopic pits (indentations) and flat areas that are in the middle layer of the flat areas that are in the middle layer of the discdisc

How a CDs and DVDs are readHow a CDs and DVDs are read

A high powered laser light creates the pits. A high powered laser light creates the pits. A lower powered laser lights reads items from the disc A lower powered laser lights reads items from the disc

by deflecting light through the bottom of the disc, which by deflecting light through the bottom of the disc, which is usually gold or silveris usually gold or silver

The reflected light is converted into a series of bits the The reflected light is converted into a series of bits the computer can processcomputer can process

A land causes the light to reflect, which is read as binary A land causes the light to reflect, which is read as binary digit 1.digit 1.

Pits absorb the light; this absence of light is read as Pits absorb the light; this absence of light is read as binary digit 0.binary digit 0.

Items are commonly store items in a single track that Items are commonly store items in a single track that spirals form the center to the outside edges of the discspirals form the center to the outside edges of the disc

Care of CDs and DVDsCare of CDs and DVDs

Never bend a disc; it may breakNever bend a disc; it may break If a disc becomes warped or if its surface is If a disc becomes warped or if its surface is

scratched, the data on the disc may be unreadablescratched, the data on the disc may be unreadable Exposing to extreme temperatures or humidity Exposing to extreme temperatures or humidity

could cause them to warp. The ideal temperature is could cause them to warp. The ideal temperature is 50-70 degrees 50-70 degrees

Stacking discs, touching the undersides or exposing Stacking discs, touching the undersides or exposing them to any type of contaminant may scratch itthem to any type of contaminant may scratch it

Best place to store the CD or DVD is in the jewel Best place to store the CD or DVD is in the jewel box that it came inbox that it came in

CD-ROMsCD-ROMs

Is used for storing Is used for storing data, instructions and data, instructions and information in addition information in addition to audio and videoto audio and video

Can only read the Can only read the content on the discs, content on the discs, meaning that they meaning that they cant be erasedcant be erased

A typical CD-ROM A typical CD-ROM can hold from 650 MB can hold from 650 MB to 1GB of datato 1GB of data

Picture CDs and Photo CDsPicture CDs and Photo CDs

Is a small data CD that Is a small data CD that stores up to one role of stores up to one role of film using a jpg file formatfilm using a jpg file format

Picture CD usually is Picture CD usually is 1024x1536 pixels1024x1536 pixels

The cost of a picture CD The cost of a picture CD is about 10 dollars per is about 10 dollars per role of filmrole of film

Stores multiple rolls of Stores multiple rolls of film using the Image Pac film using the Image Pac or PCDor PCD

Designed for commercial Designed for commercial and professional users and professional users

Resolutions ranging from Resolutions ranging from 128x192 to 4096x6144 128x192 to 4096x6144 pixelspixels

Store images from 35mm Store images from 35mm film, negatives, slides and film, negatives, slides and scanned itemsscanned items

CD-Rs and CD-RWsCD-Rs and CD-RWs

Multi session CD which Multi session CD which user put there own user put there own information on toinformation on to

To be able to write on the To be able to write on the CD-R you need a CD-R CD-R you need a CD-R drive to burn the CDdrive to burn the CD

Has a speed of 40x or Has a speed of 40x or moremore

CD-RW is a rewritable CD-RW is a rewritable CD that can be erased.CD that can be erased.

Is much like a floppy discIs much like a floppy disc Only down fall is that the Only down fall is that the

more it is erased the more it is erased the more faulty the CD more faulty the CD becomesbecomes

The CD-RW drive has a The CD-RW drive has a speed of 52x or morespeed of 52x or more

DVD-ROMsDVD-ROMs DVD stands for digital versatile DVD stands for digital versatile

disc or digital video discdisc or digital video disc Can store up from 4.7GB to 17 Can store up from 4.7GB to 17

GB the storing capacity has GB the storing capacity has more than enough to hold a more than enough to hold a telephone book containing telephone book containing every resident in the United every resident in the United StatesStates

The goal of the DVD The goal of the DVD technology is to meet the technology is to meet the needs for home entertainment, needs for home entertainment, computer usage and business computer usage and business datadata

DVD-ROM players can read DVD-ROM players can read up to speeds 48x or moreup to speeds 48x or more

Look just like the CD-ROM and Look just like the CD-ROM and sometimes are easily confusedsometimes are easily confused

First involves making the disc First involves making the disc denser by packing the pits denser by packing the pits closer togethercloser together

Second involves using two Second involves using two layers of pits. For this to work layers of pits. For this to work the lower layer of pits is the lower layer of pits is semitransparent so the laser semitransparent so the laser can be read through the upper can be read through the upper level. This technique doubles level. This technique doubles the storage capacity of the discthe storage capacity of the disc

Finally some discs are double Finally some discs are double sided and need to turn it over sided and need to turn it over when you are done with the when you are done with the one sideone side

DVD-ROM Storage CapacitiesDVD-ROM Storage Capacities

SidesSides LayersLayers Storage CapacitiesStorage Capacities

11 11 4.7 GB4.7 GB

11 22 8.5 GB8.5 GB

22 11 9.4 GB9.4 GB

22 22 17 GB17 GB